grpc++_unsecure shouldn't depend on grpc but on grpc_unsecure.
diff --git a/grpc.gemspec b/grpc.gemspec
index 00113cb..59c27fd 100755
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -146,6 +146,7 @@
   s.files += %w( include/grpc/compression.h )
   s.files += %w( include/grpc/grpc.h )
   s.files += %w( include/grpc/grpc_posix.h )
+  s.files += %w( include/grpc/grpc_security_constants.h )
   s.files += %w( include/grpc/status.h )
   s.files += %w( include/grpc/impl/codegen/byte_buffer.h )
   s.files += %w( include/grpc/impl/codegen/byte_buffer_reader.h )
@@ -169,7 +170,6 @@
   s.files += %w( include/grpc/impl/codegen/sync_windows.h )
   s.files += %w( include/grpc/impl/codegen/time.h )
   s.files += %w( include/grpc/grpc_security.h )
-  s.files += %w( include/grpc/grpc_security_constants.h )
   s.files += %w( include/grpc/census.h )
   s.files += %w( src/core/lib/channel/channel_args.h )
   s.files += %w( src/core/lib/channel/channel_stack.h )